A ultra-thin silicon nitride barrier layer implementation for silicon quantum dots in amorphous silicon carbide matrix in photovoltaic application

To search a suitable material candidate for “all-Si” tandem solar cell, a hybrid super-lattice structure consisting 30 periods of alternating amorphous Si0.7C0.3 (5 nm) layers and ultra-thin Si3N4 barrier layers (0.2-2.0 nm) has been deposited by magnetron sputtering with subsequent annealing by a rapid thermal annealing (RTA) process. Structural and electrical characterization of the layered film was carried out after annealing. 8 nm barrier layer thickness is proven to be able to provide sufficient structural confinement even after high temperature annealing. Increased resistivity was measured for the overall multi-layer structure, resulting from the incorporation of the Si3N4 barrier layers hence likely suppressing carrier transport and further electron hopping is proven the main transportation mechanism.